Demand for Apple's upcoming iPhone 5s and iPhone 5c is healthy, a new survey has found, suggesting that investor concerns over device preorders may be unfounded.

The latest AlphaWise data from Morgan Stanley tracking Web search trends found that demand for the iPhone saw a healthy uptick following last week's announcement of the iPhone 5s and iPhone 5c. The data tracks key markets where the iPhones are set to launch, including the U.S., U.K., Germany, France, China and Japan.

Analyst Katy Huberty said the survey data suggests Apple may ship 34.5 million iPhone units in the current September quarter, which will conclude less than two weeks after the iPhone 5s and iPhone 5c become available.

That would suggest a 15 percent quarter over quarter increase in iPhone shipments for the September frame, which would be in line with the 16 percent quarter over quarter increase Apple saw in the same period in 2012. To Huberty, that represents "healthy demand" for Apple's latest iPhones.

While Apple didn't announce iPhone 5c preorders this year, 2013 also marks the first time that Apple will release two new iPhone models. The iPhone 5s is not available for preorder.Shares of Apple tumbled earlier this week, when Apple declined to announce any presale figures for the iPhone 5c. For the last few years, Apple has touted record preorders for its latest iPhone  but 2013 marks the first time Apple is releasing two distinct new iPhone models, and preorders are only available for the second-tier iPhone 5c.

As a result, Huberty said investor concern over the lack of an announcement may be "overblown." She noted that Wall Street consensus calls for Apple to have shipped around 31 million iPhones in the September quarter, a figure less than the latest survey data suggests the company will actually ship.

"We don't view preorders in 2013 as comparable to past years given the higher-end iPhone 5s, which is the more likely choice for early adopters, isn't available for pre-order," Huberty wrote in a note to investors.

The multi-colored iPhone 5c remains available in stock for preorder through Apple's online store. But that model has largely the same parts as last year's iPhone 5, and lacks the Touch ID fingerprint scanner found in the new iPhone 5s, making it potentially a less attractive option for early adopters. Some observers, such as Huberty, presume the iPhone 5c will appeal to the type of customers who may not be inclined to preorder the latest smartphones.

Customers will be able to get their hands on both the iPhone 5c and iPhone 5s this Friday, when Apple's retail stores open at 8 a.m. local time. Evidence suggests the iPhone 5s will be in short supply for the launch weekend, potentially due to component constraints.